Background

Seasonally dry tropical forests (SDTF) are among the most vulnerable ecosystems to chronic anthropogenic disturbances (CAD) such as agriculture, livestock and exploitation of wood and non-timber forest products which can negatively affect the local biota. We evaluated the influence of CAD and rainfall on the diversity of flesh flies (Diptera, Sarcophagidae) in the Brazilian Caatinga. We expected that the increase in CAD would negatively affect the specialist Sarcophagidae species and promote homogenisation of the assemblage.

Methods

Specimens were collected using traps baited with fish, bovine spleen or human feces in six environments with different intensities of CAD—low, intermediate and high, based on land use and conservation status.

Results

We collected 29,810 specimens (3760 males, identified to 14 genera, 32 species). We observed a positive relationship between disturbance intensity and the abundance of synanthropic flies, mainly Tricharaea occidua. The diversity of common species and dominant species were affected only by CAD. There was also a marked substitution of species throughout the Caatinga environments (βSIM = 0.91), with few taxa (less than 50%) occurring indiscriminately in the areas under the three levels of impact.

Discussion

Chronic disturbances pose a constant threat to the conservation of flesh fly species. CAD act as a trigger for the homogenisation of Sarcophagidae assemblages, and magnify the dominance of synanthropic and generalist species.

Implications for insect conservation

Empirical data on the effect of chronic disturbances can subsidize quantitative studies addressing local extinction. Our data strengthen the use of Sarcophagidae as biological indicators of anthropogenic action and can subsidize protocols for monitoring anthropogenic impacts in dry forests.

中文翻译：

---

慢性人为干扰对季节性干燥热带森林地区果蝇（双翅目，石棺科）组合的影响

背景

季节性干燥的热带森林（SDTF）是最容易受到慢性人为干扰（CAD）的生态系统之一，例如农业，畜牧业以及对木材和非木材林产品的开采，它们会对当地生物群产生负面影响。我们评估了CAD和降雨对巴西卡廷加果蝇（Diptera，Sarcophagidae）多样性的影响。我们预期CAD的增加会对专业的石棺科物种产生负面影响，并促进组合的均质化。

方法

根据土地利用和保护状况，在六种具有不同CAD强度的环境中（低，中和高），使用用鱼，牛脾或人粪便诱捕的标本收集样本。

结果

我们收集了29,810个标本（3760名男性，鉴定为14属32种）。我们观察到干扰强度与主要蝇科特里克蝇（Trchareaea occidua）的蝇类丰富度之间呈正相关。常见物种和优势物种的多样性仅受CAD影响。在整个Caatinga环境中，物种的替代也很明显（βSIM= 0.91），在这三种影响水平下，几乎没有分类群（少于50％）发生。

讨论

慢性干扰对果蝇物种的保护构成了持续的威胁。CAD是石棺科组合均质化的触发因素，并放大了人类和通配物种的主导地位。

对昆虫保护的意义

关于慢性干扰影响的经验数据可以为解决局部灭绝的定量研究提供补贴。我们的数据加强了石棺科作为人类活动的生物学指标的使用，并可以为监测干旱森林中人为影响的方案提供补贴。